Rotation angle detection device that converts m-phase windings into two-phase windings and dynamo-electric machine using the same

ABSTRACT

Disclosed are a rotation angle detection device including: a stator provided with a one-phase excitation winding and two-phase output windings; and a rotor having salient poles, and a dynamo-electric machine using the same. The two-phase output windings are wound around a plurality of teeth of the stator, and respective numbers of turns of the two-phase output windings are obtained by using m-phase windings (m is an integer of 3 or more) imaginarily defined to convert the numbers of turns of the m-phase windings into those of two-phase windings. Thus, since the number of phases decreases compared with the case in which the windings are structured with m phases, a structure is simplified, and a manufacturing process is facilitated.

TECHNICAL FIELD

The present invention relates to a rotation angle detection device and adynamo-electric machine using the same.

BACKGROUND ART

There has been conventionally devised a rotation angle detection device,which utilizes a change in permeance of a gap between a rotor and astator, as a device which is simple in its structure and inexpensive,and at the same time, can withstand even a high temperature environmentas opposed to an optical encoder which is limited in its operatingtemperature environment and is complicated in its structure andexpensive. For example, an example of a rotation angle detection devicehaving excitation windings of two phases and a one-phase output windingis described in JP 62-58445 B. In addition, an example of a rotationangle detection device having an excitation winding of one phase andoutput windings of two phases is described in JP 49-124508 A. In boththe examples, since a rotor is formed to have salient poles, a phase oran amplitude of a voltage induced in an output winding changes dependingon an angle of the rotor, and a position of the rotor can be found byreading the change. In addition, a rotation angle detection devicehaving excitation windings of three phases is disclosed in JapanesePatent No. 2624747. Moreover, an example in which a winding isconcentrically wound around teeth of a stator and the number of turns ischanged in a sine wave shape is disclosed in Japanese Patent No. 3103487and Japanese Patent No. 3182493.

Examples of the conventional rotation angle detection device are shownin FIGS. 73 and 74. FIG. 73 shows, as a conventional example, an exampleof the rotation angel detection device in which a shaft multiple angleis 1 and the number of teeth of a stator is four, which is the same asthe rotation angle detection device disclosed in JP 49-124508 A. On theother hand, FIG. 74 shows an example of the rotation angle detectiondevice in which a shaft multiple angle is 4 and the number of teeth of astator is sixteen. In those figures, reference numeral 100 denotes astator; 101, a rotor; 102, four teeth provided in the stator 100; and103, a winding wound around the teeth 102. In a system of FIG. 73, asthe shaft multiple angle increases, the number of teeth also increasesin proportion thereto. For example, in the case in which the shaftmultiple angle is changed to 4, the structure changes to the one asshown in FIG. 74, the number of teeth increases to as many as sixteen,and winding workability deteriorates. Thus, it can be said that this isa structure not suitable for mass production.

The above-mentioned conventional examples have the following problems.If the winding structures as disclosed in JP 62-58445 B and JP 49-124508A are adopted, there is a problem in that, in the case in which theshaft multiple angle increases, the number of teeth of the stator alsoincreases in proportion thereto as described above, and a windingproperty and a machining property deteriorate.

In both of JP 62-58445 Band JP 49-124508 A, the shaft multiple angleisland the number of teeth of the stator is four. For example, in thecase in which the shaft multiple angle is changed to 2, the number ofteeth increases to eight, in the case in which the shaft multiple angleis changed to 4, the number of teeth increases to sixteen, and in thecase in which the shaft multiple angle is change to 8, the number ofteeth increases to as many as thirty-two. Although a rotation angledetection device with a large shaft multiple angle may be required in amultipolar motor, if the shaft multiple angle is large in suchconventional examples, the rotation angle detection device has astructure which is unrealistic in terms of mass productivity.

In the structure as disclosed in Japanese Patent No. 2624747, windingsare one phase for output and three phases for excitation. That is, thenumber of phase is large. Thus, there is a problem of productivity inthat winding takes time and a problem in that a power supply for theexcitation windings becomes expensive.

In the examples of Japanese Patent No. 3103487 and Japanese Patent No.3182493, since a winding is wound concentrically around the teeth of thestator, automatic winding by a machine is enabled. However, since thenumber of turns is changed in a sine wave shape, there are teeth towhich only a small number of turns are applied. A nozzle of a windingmachine for automatic winding has to be moved to the teeth to which onlya small number of turns are applied. Thus, since time is taken forpositioning of the nozzle, there is a problem in that efficiency ofwinding work is low.

The present invention has been made in order to solve such problems, andtherefore it is an object of the present invention to obtain a rotationangle detection device with a simple manufacturing process and adynamo-electric machine using the same.

DISCLOSURE OF THE INVENTION

A rotation angle detection device according to the present inventionincludes: a stator provided with a one-phase excitation winding andtwo-phase output windings; and a rotor having salient poles, and in therotation angle detection device, the two-phase output windings are woundaround a plurality of teeth of the stator, and respective numbers ofturns of the two-phase output windings are obtained by using m-phasewindings (m is an integer of 3 or more) defined in advance to convertthe numbers of turns of the m-phase windings into those of two-phasewindings.

In this way, according to the present invention, the respective numbersof turns of the two-phase output windings are obtained by using them-phase windings (m is an integer of 3 or more) defined in advance toconvert the number of turns of the m-phase windings into those oftwo-phase windings. Thus, the number of phases decreases from m to two,a structure is simplified, and a manufacturing process is facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a structure of a rotation angle detectiondevice in accordance with a first embodiment of the present invention;

FIG. 2 is a vector diagram with respect to a magnetic flux of a spatialfirst order in the rotation angle detection device in accordance withthe first embodiment of the present invention;

FIG. 3 is a vector diagram with respect to a magnetic flux of a spatialninth order in the rotation angle detection device in accordance withthe first embodiment of the present invention;

FIG. 4 is a vector diagram with respect to a magnetic flux of a spatialfifth order in the rotation angle detection device in accordance withthe first embodiment of the present invention;

FIG. 5 is an explanatory view showing, in a table format, an example ofa five-phase windings in the rotation angle detection device inaccordance with the first embodiment of the present invention;

FIG. 6 is an explanatory view showing, in a table format, an example ofwindings after five-phase-to-two-phase conversion in the rotation angledetection device in accordance with the first embodiment of the presentinvention;

FIG. 7 is an explanatory view showing, in a table format, an example ofspecific windings (in the case in which decimals are allowed for thenumber of turns) in the rotation angle detection device in accordancewith the first embodiment of the present invention;

FIG. 8 is an explanatory view showing, in a table format, an example ofspecific windings (in the case in which the number of turns is aninteger) in the rotation angle detection device in accordance with thefirst embodiment of the present invention;

FIG. 9 is an explanatory view showing, in a graph format, output voltagewaveforms of two phases (in the case of winding specifications of FIG.7) in the rotation angle detection device in accordance with the firstembodiment of the present invention;

FIG. 10 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases (in the case of winding specificationsof FIG. 8) in the rotation angle detection device in accordance with thefirst embodiment of the present invention;

FIG. 11 is a diagram showing a structure of a rotation angle detectiondevice in accordance with a second embodiment of the present invention;

FIG. 12 is a vector diagram with respect to a magnetic flux of a spatialfirst order in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 13 is a vector diagram with respect to a magnetic flux of a spatialseventh order in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 14 is a vector diagram with respect to a magnetic flux of a spatialthird order in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 15 is an explanatory view showing, in a table format, an example ofa three-phase windings in the rotation angle detection device inaccordance with the second embodiment of the present invention;

FIG. 16 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the second embodiment of the presentinvention;

FIG. 17 is an explanatory view showing, in a table format, an example ofspecific windings (in the case in which decimals are allowed for thenumber of turns) in the rotation angle detection device in accordancewith the second embodiment of the present invention;

FIG. 18 is an explanatory view showing, in a table format, an example ofspecific windings (in the case in which the number of turns is aninteger) in the rotation angle detection device in accordance with thesecond embodiment of the present invention;

FIG. 19 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases (in the case of winding specificationsof FIG. 17) in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 20 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases (in the case of winding specificationsof FIG. 18) in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 21 is a diagram showing a modification of the structure of therotation angle detection device in accordance with the second embodimentof the present invention;

FIG. 22 is an explanatory view showing, in a table format, an examplewith a shaft multiple angle of 2 and the number of slots of nine in therotation angle detection device in accordance with the second embodimentof the present invention (FIG. 21);

FIG. 23 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the second embodiment of the presentinvention (FIG. 21);

FIG. 24 is an explanatory view showing, in a table format, an example ofspecific windings (in the case in which decimals are allowed for thenumber of turns) in the rotation angle detection device in accordancewith the second embodiment of the present invention (FIG. 21);

FIG. 25 is an explanatory view showing, in a table format, an example ofspecific windings (in the case in which the number of turns is aninteger) in the rotation angle detection device in accordance with thesecond embodiment of the present invention (FIG. 21);

FIG. 26 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases (in the case of winding specificationsof FIG. 24) in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 27 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases (in the case of winding specificationsof FIG. 25) in the rotation angle detection device in accordance withthe second embodiment of the present invention;

FIG. 28 is a diagram showing a structure of a rotation angle detectiondevice in accordance with a third embodiment of the present invention;

FIG. 29 is an explanatory view showing, in a table format, an example ofthree-phase windings in the rotation angle detection device inaccordance with the third embodiment of the present invention;

FIG. 30 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the third embodiment of the presentinvention;

FIG. 31 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the third embodiment of the present invention;

FIG. 32 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases in the rotation angle detection devicein accordance with the third embodiment of the present invention;

FIG. 33 is a diagram showing a modification of the structure of therotation angle detection device in accordance with the third embodimentof the present invention;

FIG. 34 is an explanatory view showing, in a table format, an example ofthree-phase windings in the rotation angle detection device inaccordance with the third embodiment of the present invention;

FIG. 35 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the third embodiment of the presentinvention;

FIG. 36 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the third embodiment of the present invention;

FIG. 37 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases in the rotation angle detection devicein accordance with the third embodiment of the present invention;

FIG. 38 is a diagram showing a structure of a rotation angle detectiondevice in accordance with a fourth embodiment of the present invention;

FIG. 39 is an explanatory view showing, in a table format, an example ofthree-phase windings in the rotation angle detection device inaccordance with the fourth embodiment of the present invention;

FIG. 40 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the fourth embodiment of the presentinvention;

FIG. 41 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the fourth embodiment of the present invention;

FIG. 42 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases in the rotation angle detection devicein accordance with the fourth embodiment of the present invention;

FIG. 43 is a diagram showing a structure of a rotation angle detectiondevice in accordance with a fifth embodiment of the present invention;

FIG. 44 is an explanatory view showing, in a table format, an example ofthree-phase windings in the rotation angle detection device inaccordance with the fifth embodiment of the present invention;

FIG. 45 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the fifth embodiment of the presentinvention;

FIG. 46 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the fifth embodiment of the present invention;

FIG. 47 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases in the rotation angle detection devicein accordance with the fifth embodiment of the present invention;

FIG. 48 is a diagram showing a modification of the structure of therotation angle detection device in accordance with the fifth embodimentof the present invention;

FIG. 49 is an explanatory view showing, in a table format, an example ofthree-phase windings in the rotation angle detection device inaccordance with the fifth embodiment of the present invention (FIG. 48);

FIG. 50 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the fifth embodiment of the presentinvention (FIG. 48);

FIG. 51 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the fifth embodiment of the present invention (FIG. 48);

FIG. 52 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases in the rotation angle detection devicein accordance with the fifth embodiment of the present invention (FIG.48);

FIG. 53 is an explanatory view showing an example in which a magneticflux of the same order as a shaft multiple angle in a rotation angledetection device in accordance with a sixth embodiment of the presentinvention;

FIG. 54 is a vector diagram with respect to a magnetic flux of a spatialfourth order in the rotation angle detection device in accordance withthe sixth embodiment of the present invention;

FIG. 55 is an explanatory view showing, in a table format, an example ofthree-phase windings (an example of windings which do not pick up amagnetic flux of the same order as a shaft multiple angle) in therotation angle detection device in accordance with the sixth embodimentof the present invention;

FIG. 56 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion (an example ofwindings which do not pick up a magnetic flux of the same order as ashaft multiple angle) in the rotation angle detection device inaccordance with the sixth embodiment of the present invention;

FIG. 57 is an explanatory view showing, in a table format, an example ofspecific windings (an example of windings which do not pick up amagnetic flux of the same order as a shaft multiple angle) in therotation angle detection device in accordance with the sixth embodimentof the present invention;

FIG. 58 is an explanatory view showing, in a graph format, outputvoltage waveforms of two phases in the rotation angle detection devicein accordance with the sixth embodiment of the present invention;

FIG. 59 is a diagram showing a structure of a rotation angle detectiondevice in accordance with an eighth embodiment of the present invention;

FIG. 60 is a vector diagram with respect to a magnetic flux of a spatialsecond order in the rotation angle detection device in accordance withthe eighth embodiment of the present invention;

FIG. 61 is a vector diagram with respect to a magnetic flux of a spatialfourth order in the rotation angle detection device in accordance withthe eighth embodiment of the present invention;

FIG. 62 is an explanatory view showing, in a table format, three-phasewindings in the rotation angle detection device in accordance with theeighth embodiment of the present invention (No. 1);

FIG. 63 is an explanatory view showing, in a table format, three-phasewindings in the rotation angle detection device in accordance with theeighth embodiment of the present invention (No. 2);

FIG. 64 is an explanatory view showing, in a table format, three-phasewindings in the rotation angle detection device in accordance with theeighth embodiment of the present invention (No. 3);

FIG. 65 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the eighth embodiment of the presentinvention (No. 1);

FIG. 66 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the eighth embodiment of the presentinvention (No. 2);

FIG. 67 is an explanatory view showing, in a table format, an example ofwindings after three-phase-to-two-phase conversion in the rotation angledetection device in accordance with the eighth embodiment of the presentinvention (No. 3);

FIG. 68 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the eighth embodiment of the present invention (No. 1);

FIG. 69 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the eighth embodiment of the present invention (No. 2);

FIG. 70 is an explanatory view showing, in a table format, an example ofspecific windings in the rotation angle detection device in accordancewith the eighth embodiment of the present invention (No. 3);

FIG. 71 is an explanatory view showing, in a graph format, a change in adetecting position error due to presence or absence of eccentricity inthe rotation angle detection device in accordance with the eighthembodiment of the present invention;

FIG. 72 is a diagram showing a structure of a ninth embodiment in whichthe rotation angle detection device in accordance with the first toeighth embodiments of the present invention is applied to a generatorhaving a field core of a claw shape;

FIG. 73 is a diagram showing an example of a structure of a conventionalrotation angle detection device; and

FIG. 74 is a diagram showing another example of the structure of theconventional rotation angle detection device.

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

Here, as an embodiment, a rotation angel detection device with a shaftmultiple angle of 4 (the number of teeth is ten, five-phase-to-two-phaseconversion) will be described. In the conventional examples shown inFIGS. 73 and 74, as described above, as a shaft multiple angleincreases, the number of teeth also increases in proportion thereto. Forexample, as in the example of FIG. 74, in the case in which the shaftmultiple angle is changed to 4, the number of teeth increases to as manyas sixteen, and winding workability falls. Thus, this is a structure notsuitable for mass production.

However, according to the present invention, even if the shaft multipleangle increases, a rotation angle detection device can be constituted byreducing the number of teeth compared with the above-mentionedconventional examples. The constitution will be hereinafter described.

FIG. 1 shows a rotation angle detection device in accordance with afirst embodiment of the present invention in which a shaft multipleangle is 4 and the number of teeth of a stator is ten. In FIG. 1,reference numeral 1 denotes a stator; 2, a rotor; 3, ten teeth providedin the stator 1; 4, a core of the stator 1; 5, a winding wound aroundthe teeth 3; 6, a core of the rotor 2; 7, four salient poles provided inthe core 6; and 10, a rotation angle detection device. As shown in FIG.1, the stator 1 is constituted by the core 4 having ten teeth 3, theone-phase excitation winding 5, and output windings of two phases (notshown). In addition, the rotor 2 is constituted by the core 6 havingfour salient poles 7 so as to function as the rotation angle detectiondevice 10 with the shaft multiple angle of 4, and is made rotatable withrespect to the stator 1.

Next, it will be explained how to constitute the one-phase excitationwinding 5 and the output windings of two phases. The excitation winding5 is concentrically wound around the respective teeth 3 with the teethnumbers 1 to 10. In addition, the excitation winding 5 is wound suchthat polarities thereof are opposite in the teeth 3 adjacent to eachother. In other words, a winding with which 10 magnetic poles can beconstituted is provided. In this case, it will be considered how theoutput windings should be wound. In order to function as a rotationangle detection device, the output windings are required to pick up amagnetic flux of a spatial order equal to:

(number of pole pairs for excitation)±(shaft multiple angle) amongmagnetic fluxes formed in a gap. Here, since the number of pole pairsfor excitation is 5 and the shaft multiple angle is 4:5±4=1, 9.

Thus, the output windings are required to pick up a magnetic flux of thespatial first order or ninth order (however, the spatial first ordermeans an order with a machine angle 360 degrees as one cycle). Inaddition, the output windings should not pick up a magnetic flux of thespatial order of the number of pole pairs for excitation or an integertimes thereof. Thus, conditions necessary for the output windings of twophases to function as the rotation angle detection device are summarizedas follows:

-   (1) pick up a magnetic flux of the spatial first order or the    spatial ninth order; and-   (2) do not pick up a magnetic flux of the spatial fifth order or an    integer times thereof.    In order to satisfy the conditions, first, considering the output    winding of five phases imaginarily, five-phase windings are    converted into two phases to have two-phase windings of a sin output    and a cos output (hereinafter referred to as a phase and β phase    windings).

First, five-phase windings satisfying the condition (1) will beconsidered. Here, this will be considered using vector diagrams. FIGS. 2and 3 show in which phase the winding with the magnetic flux of thespatial first order or the ninth order wound around the respective teethlinks. Each vector number represents a teeth number, and indicates aphase of a magnetic flux in which a winding wound around the respectiveteeth numbers links. It is assumed that the phase advancescounterclockwise. From the vector diagrams, if the winding is applied tothe teeth numbers 1, 5, and 7 and a polarity of the teeth numbers 5 and7 is set to a polarity opposite to that of the teeth 1, both magneticfluxes of the spatial first order and the spatial ninth order can bepicked up. If windings deviating from this winding by an electricalangle of 72 degrees are constituted for the remaining four phases, themagnetic fluxes of the spatial first order and the spatial ninth orderfor functioning as the rotation angle detection device are picked up,and the windings of five phases deviating by the electrical angle of 72degrees, respectively, can be constituted (provided that the electricalangle is assumed to be an angle found by multiplying a machine angle bya shaft multiple angle). In other words, winding specifications as shownin a table of FIG. 5 are obtained. Here, the number of turns isrepresented by ±1.0 in order to standardize the number, and a differenceof signs represents a difference of polarities. In addition, parts of0.0 indicate the parts which a winding is not applied to.

The output windings of five phases satisfying the condition (1) areformed as described above. If the windings remain in five phases, thewindings do not satisfy the condition (2) and, in addition, even if theoutput windings function as the rotation angle detection device, aprocessing circuit becomes complicated and expensive. Thus, in order toconvert the five-phase windings into two-phase winding (α phase, βphase), five-phase-to-two-phase conversion as indicated by the followingexpression (1) is defined.

$\begin{matrix}{\begin{pmatrix}N_{\alpha} \\N_{\beta}\end{pmatrix} = {{k\left( {\begin{matrix}{\cos\;\gamma} & {\cos\left( {\gamma + \frac{2\pi}{5}} \right)} & {\cos\left( {\gamma + \frac{4\pi}{5}} \right)} \\{\sin\;\gamma} & {\sin\left( {\gamma + \frac{2\pi}{5}} \right)} & {\sin\left( {\gamma + \frac{4\pi}{5}} \right)}\end{matrix}\begin{matrix}{\mspace{85mu}{\cos\left( {\gamma + \frac{6\pi}{5}} \right)}} & {\cos\left( {\gamma + \frac{8\pi}{5}} \right)} \\{\mspace{85mu}{\sin\left( {\gamma + \frac{6\pi}{5}} \right)}} & {\sin\left( {\gamma + \frac{8\pi}{5}} \right)}\end{matrix}} \right)}\begin{pmatrix}N_{1} \\N_{2} \\N_{3} \\N_{4} \\N_{5}\end{pmatrix}}} & (1)\end{matrix}$

Here, k represents a constant, N_(α) and N_(β) represent the numbers ofturns of the α phase and β phase output windings, respectively and Ni(i=1, . . . , 5) represents the number of turns of the i-th outputwinding. In addition, γ represents an arbitrary angle.

If the numbers of turns of the respective teeth are determined byfive-phase-to-two-phase conversion represented by expression (1),magnetic fluxes linking with the windings are also subjected to thefive-phase-to-two-phase conversion. In addition, the condition (2) issatisfied by this five-phase-to-two-phase conversion. This is because,according to a vector diagram (FIG. 4) for a magnetic flux of thespatial fifth order, it is evident that the phase is the same in thewindings of five phases and, in this case, the magnetic flux iscancelled by means of the condition (1). Thus, it is observed that thecondition (2) is satisfied by the five-phase-to-two-phase conversion,and the output windings of two phases has winding specifications forfunctioning as the rotation angel detection device. Then, an example inwhich γ and k are specifically assumed to be 0 and 1, respectively, inexpression (1) and FIG. 5 is subjected to the five-phase-to-two-phaseconversion is shown in FIG. 6. However, a number is rounded off to thefourth decimal place. The realistic numbers of turns which are decidedspecifically on the basis of FIG. 6 are shown in FIGS. 7 and 8. Valuesobtained by multiplying the numbers of turns in FIG. 6 by 50 and 100 areindicated for excitation windings and output windings, respectively. Inaddition, FIG. 7 shows a case in which decimals are allowed for thenumber of turns (ideal case). FIG. 8 shows the case in which decimalsare rounded off.

Graphs of FIGS. 9 and 10 show how a voltage appearing in the outputwindings of two phases is changed by a rotor position when the windingspecifications are set as shown in FIGS. 7 and 8 and excitation windingsare excited by an AC current. In these figures, reference numeral 20denotes an α phase winding and 21 denotes a β phase winding. Inaddition, the horizontal axis indicates a position of a rotor with amachine angle, and the vertical axis indicates a voltage generated inthe output windings. Note that a minus sign of a voltage indicates thata phase is reversed with respect to an electric current of theexcitation windings. In both cases, since voltages deviate by anelectric angle of 90 degrees from each other in a waveform of a sinewave shape, it was confirmed that the output windings operate as therotation angle detection device.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of five phases, and then subjectingthe output windings to the five-phase-to-two-phase conversion.Accordingly, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there isobtained an effect in that a structure is simplified and a manufacturingprocess is facilitated. Moreover, in the conventional examples, thenumber of teeth of a stator is 16 in the case in which a shaft multipleangle is 4, whereas, according to the present invention, it issufficient that the number of teeth is 10. In other words, since therotation angle detection device can be constituted with the smallernumber of teeth than the conventional examples even if the shaftmultiple angle increases, there is also an effect in that the rotationangle detection device has satisfactory winding property and machiningproperty and is excellent in mass productivity. Moreover, in theconventional examples, the number of turns may be changed in a sine waveshape. In this case, there are teeth to which only a small number ofturns are applied. Since positioning of a nozzle of a winding machinefor automatic winding, which takes time, is required to be performed forthe teeth, there is a problem in that efficiency of winding work falls.In the present invention, as it is evident from FIGS. 6, 7, and 8, thereare a plurality of teeth to which output windings may not be applied,thus having an effect in that efficiency of winding work can beimproved.

Although the five-phase-to-two-phase conversion is described above,output windings operating as the rotation angle detection device canalso be obtained by generally converting m phases (m is an integer of 3or more) into two phases. In that case, it is sufficient to definem-phase-to-two-phase conversion as described below.

$\begin{matrix}{N_{\alpha\; i} = {k{\sum\limits_{n = 1}^{m}{N_{ni}{\cos\left( {\gamma + {\frac{2\left( {n - 1} \right)}{m}\pi}} \right)}}}}} & (2) \\{N_{\beta\; i} = {k{\sum\limits_{n = 1}^{m}{N_{ni}{\sin\left( {\gamma + {\frac{2\left( {n - 1} \right)}{m}\pi}} \right)}}}}} & (3)\end{matrix}$

Here, in expressions (2) and (3), γ represents an arbitrary constant, krepresents an arbitrary constant excluding zero, a subscript irepresents a number of a tooth, α and β represent two-phase windingsafter conversion, and n represents nth phase before conversion. In otherwords, N_(αi) and N_(βi) represent the number of turns of the α-phaseand β-phase windings in the i-th tooth, respectively, and N_(ni)represents the number of turns of nth phase winding of the i-th tooth.It is needless to mention that the same effects can be obtained from thewindings constituted by converting the windings of m phases into twophases in this way. In addition, the numbers of turns of the respectiveteeth of the rotation angle detection device in the present inventionare not required to be strictly identical with the numbers of turnsdecided by the m-phase-to-two-phase conversion. For example, as shown inFIGS. 9 and 10, the output windings function as the rotation angledetection device without any problem regardless of whether decimals arerounded off or not as already described. Moreover, for example, even ifthe number of turns deviates by about 10% from the number of turnsdecided by the m-phase-to-two-phase conversion, a sine wave in FIG. 10simply deviates by about 10%. It is needless to mention that theabove-mentioned effects are not spoiled, and the output windings operateas the rotation angle detection device.

Second Embodiment

In this embodiment, an example of constituting windings usingthree-phase-to-two-phase conversion will be described, while in thefirst embodiment, the specific examples of the five-phase-to-two-phaseconversion and the method of converting the general windings of m phasesinto two phases are described.

FIG. 11 shows a rotation angle detection device in which a shaftmultiple angle is 4 and the number of teeth is 9. In this embodiment,the number of teeth is set to 3n (n is a natural number; here, n=3). InFIG. 11, reference numeral 1 denotes a stator; 2, a rotor; 3, nine teethprovided in the stator 1; 4, a core of the stator 1; 5, a winding woundaround the teeth 3; 6, a core of the rotor 2; 7, four salient polesprovided in the core 6; and 10, a rotation angle detection device. Thestator 1 is constituted by the core 4 having nine teeth 3, the one-phaseexcitation winding 5, and output windings of two phases (not shown). Inaddition, the rotor 2 is constituted by the core 6 having four salientpoles 7 so as to function as the rotation angle detection device 10 withthe shaft multiple angle of 4, and is made rotatable with respect to thestator 1.

Next, it will be explained how to constitute the one-phase excitationwinding 5 and the output windings of two phases. The excitation winding5 is concentrically wound around the respective teeth 3 with the teethnumbers 1 to 9. The excitation winding 5 is wound such that a windingwith which 6 magnetic poles can be constituted. In this case, it will beconsidered how the output windings should be wound. In order to functionas a rotation angle detection device, the output windings are requiredto pick up a magnetic flux of a spatial order equal to:

(number of pole pairs for excitation)±(shaft multiple angle) amongmagnetic fluxes formed in a gap. Here, since the number of pole pairsfor excitation is 3 and the shaft multiple angle is 4:4±3=1, 7

Thus, the output windings are required to pick up a magnetic flux of thespatial first order or seventh order (however, the spatial first ordermeans an order with a machine angle 360 degrees as one cycle). Inaddition, the output windings should not pick up a magnetic flux of thespatial order of the number of pole pairs for excitation or an integertimes thereof. Thus, conditions necessary for the output windings of twophases to function as the rotation angle detection device are summarizedas follows:

-   (1) pick up a magnetic flux of the spatial first order or the    spatial seventh order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    In order to satisfy the conditions, first, considering the output    winding of three phases (U phase, V phase, and W phase) imaginarily,    three-phase windings are converted into two phases to have two-phase    windings of a sin output and a cos output (hereinafter referred to    as α phase and β phase windings).

First, three-phase windings satisfying the condition (1) will beconsidered. Here, this will be considered using vector diagrams. FIGS.12 and 13 show in which phase the winding with the magnetic flux of thespatial first order or the seventh order wound around the respectiveteeth links. Each vector number represents a teeth number, and indicatesa phase of a magnetic flux in which a winding wound around therespective teeth numbers links. It is assumed that the phase advancescounterclockwise. From the vector diagrams, if the winding is applied tothe teeth numbers 1, 5, and 6 and a polarity of the teeth numbers 5 and6 is set to a polarity opposite to that of the teeth 1, a magnetic fluxof the spatial first order can be picked up. If windings deviating fromthis winding by an electrical angle of 120 degrees are constituted forthe remaining three phases, the magnetic fluxes of the spatial firstorder and the spatial seventh order for functioning as the rotationangle detection device are picked up, and the windings of three phasesdeviating by the electrical angle of 120 degrees, respectively, can beconstituted (provided that the electrical angle is assumed to be anangle found by multiplying a machine angle by a shaft multiple angle).In other words, winding specifications as shown in a table of FIG. 15are obtained. Here, the number of turns is represented by ±1.0 in orderto standardize the number, and a difference of signs represents adifference of polarities. In addition, parts of 0.0 indicate the partswhich a winding is not applied to.

The output windings of three phases satisfying the condition (1) areformed as described above. If the windings remain in three phases, thewindings do not satisfy the condition (2) and, in addition, even if theoutput windings function as the rotation angle detection device, aprocessing circuit becomes complicated and expensive. Thus, in order toconvert the three-phase windings into two-phase winding (α phase, βphase), three-phase-to-two-phase conversion as indicated by thefollowing expression (4) is defined.

$\begin{matrix}{\begin{pmatrix}N_{\alpha} \\N_{\beta}\end{pmatrix} = {{k\begin{pmatrix}{\cos\;\gamma} & {\cos\left( {\gamma + \frac{2\pi}{3}} \right)} & {\cos\left( {\gamma - \frac{2\pi}{3}} \right)} \\{\sin\;\gamma} & {\sin\left( {\gamma + \frac{2\pi}{3}} \right)} & {\sin\left( {\gamma - \frac{2\pi}{3}} \right)}\end{pmatrix}}\begin{pmatrix}N_{U} \\N_{V} \\N_{W}\end{pmatrix}}} & (4)\end{matrix}$

If the numbers of turns of the respective teeth are determined bythree-phase-to-two-phase conversion represented by expression (4),magnetic fluxes linking with the windings are also subjected to thethree-phase-to-two-phase conversion. In addition, the condition (2) issatisfied by this three-phase-to-two-phase conversion. This is because,according to a vector diagram (FIG. 14) for a magnetic flux of thespatial third order, it is evident that the phase is the same in thewindings of three phases, and in this case, the magnetic flux iscancelled by the expression (4). Thus, it is observed that the condition(4) is satisfied by the three-phase-to-two-phase conversion, and theoutput windings of two phases has winding specifications for functioningas the rotation angel detection device. Then, an example in which γ andk are specifically assumed to be 0 and (⅔)^(1/2), respectively, inexpression (4) and the three-phase windings in FIG. 15 is subjected tothe three-phase-to-two-phase conversion is shown in FIG. 16. However, anumber is rounded off to the fourth decimal place. The realistic numbersof turns which are decided specifically on the basis of FIG. 16 areshown in FIGS. 17 and 18. Values obtained by multiplying the numbers ofturns in FIG. 16 by 50 and 150 are indicated for excitation windings andoutput windings, respectively. In addition, FIG. 17 shows a case inwhich decimals are allowed for the number of turns (ideal case). FIG. 18shows the case in which decimals are rounded off.

Graphs of FIGS. 19 and 20 show how a voltage appearing in the outputwindings of two phases is changed by a rotor position when the windingspecifications are set as shown in FIGS. 17 and 18 and excitationwindings are excited by an AC current. In these figures, referencenumeral 20 denotes an α phase winding and 21 denotes a β phase winding.In addition, the horizontal axis indicates a position of a rotor with amachine angle, and the vertical axis indicates a voltage generated inthe output windings. Note that a minus sign of a voltage indicates thata phase is reversed with respect to an electric current of theexcitation windings. In both cases, since voltages deviate by anelectric angle of 90 degrees (machine angle of 22.5 degrees) from eachother in a waveform of a sine wave shape, it was confirmed that theoutput windings operate as the rotation angle detection device with theshaft multiple angle of 4.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of three phases and, then, subjectingthe output windings to the three-phase-to-two-phase conversion.Accordingly, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there is aneffect in that a structure is simplified. Moreover, in the conventionalexamples, the number of teeth of a stator is sixteen in the case inwhich a shaft multiple angle is 4, whereas, according to the presentinvention, it is sufficient that the number of teeth is nine. In otherwords, since the rotation angle detection device can be constituted withthe smaller number of teeth than the conventional examples even if theshaft multiple angle increases, there is also an effect in that therotation angle detection device has satisfactory winding property andmachining property and is excellent in mass productivity. Moreover, inthe conventional examples, the number of turns may be changed in a sinewave shape. In this case, there are teeth to which only a small numberof turns are applied. Since positioning of a nozzle of a winding machinefor automatic winding, which takes time, is required to be performed forthe teeth, there is a problem in that efficiency of winding work falls.In the present invention, as it is evident from FIGS. 17 and 18, thereare a plurality of teeth to which output windings may not be applied,there is an effect in that efficiency of winding work can be improved.In addition, since multiphase windings, which are constitutedimaginarily, can be constituted in three phases in constituting outputwindings of two phases, there is an effect in that specifications ofoutput windings can be decided easily.

Although only the case in which the shaft multiple angle is 4 isdescribed above, other shaft multiple angles can also be structured in asimilar procedure. FIG. 21 shows an example in which a shaft multipleangle is 2 and the number of teeth is nine. In FIG. 21, referencenumeral 1 denotes a stator; 2, a rotor; 3, nine teeth provided in thestator 1; 4, a core of the stator 1; 5, a winding wound around the teeth3; 6, a core of the rotor 2; 7, two salient poles provided in the core6; and 10, a rotation angle detection device. When it is assumed thatthe number of poles of the excitation winding is 6, conditions for theexcitation winding to operate as the rotation angle detection device arefound as follows in the same manner in consideration of the fact thatthe shaft multiple angle is 2:

-   (1) pick up a magnetic flux of the spatial first order or the    spatial fifth order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    FIG. 22 shows an example of three-phase windings satisfying the    condition (1). FIG. 23 shows the three-phase windings which are    subjected to the three-phase-to-two-phase conversion in accordance    with expression (4) to satisfy the condition (2). Note that γ=0 and    k=(⅔)^(1/2). However, a number is rounded off to the fourth decimal    place. The realistic numbers of turns which are decided specifically    on the basis of FIG. 23 are shown in FIGS. 24 and 25. Values    obtained by multiplying the numbers of turns in FIG. 23 by 50 and    150 are indicated for excitation windings and output windings,    respectively. In addition, FIG. 24 shows a case in which decimals    are allowed for the number of turns (ideal case), and decimals are    rounded off in FIG. 25. Graphs of FIGS. 26 and 27 show how a voltage    appearing in the output windings of two phases is changed by a rotor    position when the winding specifications are set as shown in FIGS.    24 and 25 and excitation windings are excited by an AC current. In    these figures, reference numeral 20 denotes an a phase winding and    21 denotes a phase winding. In addition, the horizontal axis    indicates a position of a rotor with a machine angle, and the    vertical axis indicates a voltage generated in the output windings.    Note that a minus sign of a voltage indicates that a phase is    reversed with respect to an electric current of the excitation    windings. In both cases, since voltages deviate by an electric angle    of 90 degrees (machine angle of 45 degrees) from each other in a    waveform of a sine wave shape, it could be confirmed that the output    windings operated as the rotation angle detection device with the    shaft multiple angle of 2.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of three phases, and then subjectingthe output windings to the three-phase-to-two-phase conversion.Accordingly, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there isobtained an effect in that a structure is simplified and a manufacturingprocess is facilitated. Moreover, in the conventional examples, thenumber of turns may be changed in a sine wave shape. In this case, thereare teeth to which only a small number of turns are applied. Sincepositioning of a nozzle of a winding machine for automatic winding,which takes time, is required to be performed for the teeth, there is aproblem in that efficiency of winding work falls. In the presentinvention, as it is evident from FIGS. 23, 24, and 25, there are aplurality of teeth to which output windings may not be applied, thushaving an effect in that efficiency of winding work can be improved. Inaddition, since multiphase windings, which are constituted imaginarily,can be constituted in three phases in constituting output windings oftwo phases, there is an effect in that specifications of output windingscan be decided easily.

In addition, in this embodiment, the number of stator teeth is an oddnumber. In the conventional examples, the number of teeth is an evennumber, and excitation windings are wound such that polarities areopposite in teeth adjacent to each other. In other words, the number ofstator teeth and the number of excitation windings are identical.However, with the conventional winding method for excitation windings,polarities of windings adjacent to each other are identical in one partin such a pattern of windings in the case in which the number of teethis an odd number. Thus, there is a problem in that well-balancedexcitation windings are not obtained, which leads to an increase in adetecting position error. On the other hand, the excitation windings ofthis embodiment are constituted differently from the conventionalexamples, and are wound so as to form one pattern with three teeth. Inother words, as shown in FIG. 41, the number of turns is 50 in the teethnumber 1, and is −25 in the teeth numbers 2 and 3 (polarity is oppositeto that of the teeth number 1). This pattern is repeated three times,that is, the number of times which is the same as a value of a divisorof 9 which is a value of the number of teeth (note that, althoughdivisors of 9 are 1 and 3, a value of a divisor other than 1 is called adivisor here). With such a constitution, since the windings of the samepattern are repeated, the excitation windings can be wound with goodbalance. In general, even in the case where the number of teeth is anodd number, windings of the same pattern are repeated the number oftimes equivalent to a divisor of the number of teeth, wherebywell-balanced excitation windings can be constituted. Accordingly, sincemagnetomotive forces of the excitation windings are generated with goodbalance, there is obtained an effect in that a detecting position errornever increases.

Moreover, in FIG. 41, the number of turns is 50 in the teeth number 1,and is −25 in the teeth numbers 2 and 3, respectively and when thenumbers of turns are totaled in the pattern (also taking into accountthe polarities), a total number of turns is calculated as 50−25−25=0. Inthis way, if the numbers of windings are set such that a total of thenumbers is zero, a magnetomotive force of the spatial 0^(th) order isnot generated when an electric current flows to the excitation windings.Accordingly, there is obtained an effect in that a magnetic flux of anunnecessary order is not generated in a gap and an increase in adetecting position error can be prevented.

Third Embodiment

FIG. 28 shows an example in which a shaft multiple angle is 4 and thenumber of teeth is six. In this embodiment, the number of teeth is setto 3n (n is a natural number; here, n=2). In FIG. 28, reference numeral1 denotes a stator; 2, a rotor; 3, six teeth provided in the stator 1;4, a core of the stator 1; 5, a winding wound around the teeth 3; 6, acore of the rotor 2; 7, four salient poles provided in the core 6; and10, a rotation angle detection device.

When it is assumed that the number of poles of the excitation winding 5is six, conditions for the excitation winding 5 to operate as therotation angle detection device are found as follows in the same mannerin consideration of the fact that the shaft multiple angle is 4:

-   (1) pick up a magnetic flux of the spatial first order or the    spatial seventh order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    FIG. 29 shows an example of three-phase windings satisfying the    condition (1). FIG. 30 shows the three-phase windings which are    subjected to the three-phase-to-two-phase conversion in accordance    with expression (4) to satisfy the condition (2). Note that γ=0 and    k=(⅔)^(1/2). However, a number is rounded off to the fourth decimal    place. The realistic numbers of turns which are decided specifically    on the basis of FIG. 30 are shown in FIG. 31. Values obtained by    multiplying the numbers of turns in FIG. 30 by 50 and 150 are    indicated for excitation windings and output windings, respectively.    Note that decimals are rounded off in FIG. 31. A graph of FIG. 32    shows how a voltage appearing in the output windings of two phases    is changed by a rotor position when the winding specifications are    set as shown in FIG. 31 and excitation windings are excited by an AC    current. In this figure, reference numeral 20 denotes an α phase    winding and 21 denotes a β phase winding. In addition, the    horizontal axis indicates a position of a rotor with a machine    angle, and the vertical axis indicates a voltage generated in the    output windings. Note that a minus sign of a voltage indicates that    a phase is reversed with respect to an electric current of the    excitation windings. In both cases, since voltages deviate by an    electric angle of 90 degrees (machine angle of 22.5 degrees) from    each other in a waveform of a sine wave shape, it was confirmed that    the output windings operate as the rotation angle detection device    with the shaft multiple angle of 4.

Further, FIG. 33 shows an example in which a shaft multiple angle is 8and the number of teeth is 6. In FIG. 33, reference numeral 1 denotes astator; 2, a rotor; 3, six teeth provided in the stator 1; 4, a core ofthe stator 1; 5, a winding wound around the teeth 3; 6, a core of therotor 2; 7, eight salient poles provided in the core 6; and 10, arotation angle detection device.

When it is assumed that the number of poles of the excitation winding is6, conditions for the excitation winding 5 to operate as the rotationangle detection device are found as follows in the same manner, payingattention to the fact that the shaft multiple angle is 8:

-   (1) pick up a magnetic flux of the spatial fifth order or the    spatial eleventh order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    FIG. 34 shows an example of three-phase windings satisfying the    condition (1). FIG. 35 shows the three-phase windings which are    subjected to the three-phase-to-two-phase conversion in accordance    with expression (4) to satisfy the condition (2). Note that γ=0 and    k=(⅔)^(1/2). However, a number is rounded off to the fourth decimal    place. The realistic numbers of turns which are decided specifically    on the basis of FIG. 35 are shown in FIG. 36. Values obtained by    multiplying the numbers of turns in FIG. 35 by 50 for excitation    windings and 150 for output windings are indicated, respectively.    Note that decimals are rounded off in FIG. 36. A graph of FIG. 37    shows how a voltage appearing in the output windings of two phases    is changed by a rotor position when the winding specifications are    set as shown in FIG. 38 and excitation windings are excited by an AC    current. In this figure, reference numeral 20 denotes an α phase    winding and 21 denotes a β phase winding. In addition, the    horizontal axis indicates a position of a rotor with a machine    angle, and the vertical axis indicates a voltage generated in the    output windings. Note that a minus sign of a voltage indicates that    a phase is reversed with respect to an electric current of the    excitation windings. In both the cases, since voltages deviate by an    electric angle of 90 degrees (machine angle of 11.25 degrees) from    each other in a waveform of a sine wave shape, it could be confirmed    that the output windings operated as the rotation angle detection    device with the shaft multiple angle of 8. Note that the windings    illustrated above are only examples. This is because there are other    windings which satisfy the condition (1) and, in addition, the    number of turns can also be changed according to γ and k.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of three phases, and then subjectingthe output windings to the three-phase-to-two-phase conversion.Accordingly, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there isobtained an effect in that a structure is simplified and a manufacturingprocess is facilitated. Moreover, in the conventional examples, thenumber of teeth of a stator is 16 in the case in which a shaft multipleangle is 4, and the number of teeth of the stator is 32 when the shaftmultiple angle is 8, whereas, according to the present invention, it issufficient that the number of teeth is 6. In other words, since therotation angle detection device can be constituted with the smallernumber of teeth than the conventional examples even if the shaftmultiple angle increases, there is also an effect in that the rotationangle detection device has satisfactory winding property and machiningproperty and is excellent in mass productivity. Moreover, in theconventional examples, the number of turns may be changed in a sine waveshape. In this case, there are teeth to which only a small number ofturns are applied. Since positioning of a nozzle of a winding machinefor automatic winding, which requires time, is required to be performedfor the teeth, there is a problem in that efficiency of winding workfalls. In the present invention, as it is evident from FIGS. 31 and 36,there are a plurality of teeth to which output windings may not beapplied, thus having an effect in that efficiency of winding work can beimproved. In addition, since multiphase windings, which are constitutedimaginarily, can be constituted in three phases in constituting outputwindings of two phases, there is an effect in that specifications ofoutput windings can be decided easily.

Fourth Embodiment

FIG. 38 shows an example in which a shaft multiple angle is 8 and thenumber of teeth is nine. In FIG. 38, reference numeral 1 denotes astator; 2, a rotor; 3, nine teeth provided in the stator 1; 4, a core ofthe stator 1; 5, a winding wound around the teeth 3; 6, a core of therotor 2; 7, eight salient poles provided in the core 6; and 10, arotation angle detection device.

When it is assumed that the number of poles of the excitation winding issix, conditions for the excitation winding 5 to operate as the rotationangle detection device are found as follows in the same manner, payingattention to the fact that the shaft multiple angle is 8:

-   (1) pick up a magnetic flux of the spatial fifth order or the    spatial eleventh order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    FIG. 39 shows an example of three-phase windings satisfying the    condition (1). FIG. 40 shows the three-phase windings which are    subjected to the three-phase-to-two-phase conversion in accordance    with expression (4) to satisfy the condition (2). Note that γ=0 and    k=(⅔)^(1/2). However, a number is rounded off to the fourth decimal    place. The realistic numbers of turns which are decided specifically    on the basis of FIG. 40 are shown in FIG. 41. Values obtained by    multiplying the numbers of turns in FIG. 40 by 50 for excitation    windings and 150 for output windings are indicated, respectively.    Note that decimals are rounded off in FIG. 41. A graph of FIG. 42    shows how a voltage appearing in the output windings of two phases    is changed by a rotor position when the winding specifications are    set as shown in FIG. 41 and excitation windings are excited by an AC    current. In this figure, reference numeral 20 denotes an α phase    winding and 21 denotes a β phase winding. In addition, the    horizontal axis indicates a position of a rotor with a machine    angle, and the vertical axis indicates a voltage generated in the    output windings. Note that a minus sign of a voltage indicates that    a phase is reversed with respect to an electric current of the    excitation windings. In both the cases, since voltages deviate by an    electric angle of 90 degrees (machine angle of 11.25 degrees) from    each other in a waveform of a sine wave shape, it could be confirmed    that the output windings operated as the rotation angle detection    device with the shaft multiple angle of 8.

Note that the windings illustrated above are only examples. This isbecause there are other windings which satisfy the condition (1) and, inaddition, the number of turns can also be changed according to γ and k.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of three phases, and then, subjectingthe output windings to the three-phase-to-two-phase conversion.Accordingly, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there isobtained an effect in that a structure is simplified and a manufacturingprocess is facilitated. Moreover, in the conventional examples, thenumber of teeth of the stator is 32 when the shaft multiple angle is 8,whereas, according to the present invention, the number of teeth isnine. In other words, since the rotation angle detection device of thepresent invention can be constituted with the smaller number of teeththan the conventional examples even if the shaft multiple angleincreases, there is also an effect in that the rotation angle detectiondevice has satisfactory winding property and machining property and isexcellent in mass productivity. Moreover, in the conventional examples,the number of turns may be changed in a sine wave shape. In this case,there are teeth to which only a small number of turns are applied. Sincepositioning of a nozzle of a winding machine for automatic winding,which requires time, is required to be performed for the teeth, there isa problem in that efficiency of winding work falls. In the presentinvention, as it is evident from FIG. 41, there are a plurality of teethto which output windings may not be applied, thus having an effect inthat efficiency of winding work can be improved. In addition, sincemultiphase windings, which are constituted imaginarily, can beconstituted in three phases in constituting output windings of twophases, there is an effect in that specifications of output windings canbe decided easily.

Fifth Embodiment

FIG. 43 shows an example in which a shaft multiple angle is 4 and thenumber of teeth is 12. In FIG. 43, reference numeral 1 denotes a stator;2, a rotor; 3, twelve teeth provided in the stator 1; 4, a core of thestator 1; 5, a winding wound around the teeth 3; 6, a core of the rotor2; 7, four salient poles provided in the core 6; and 10, a rotationangle detection device.

When it is assumed that the number of poles of the excitation winding is6, conditions for the excitation winding 5 to operate as the rotationangle detection device are found as follows in the same manner, payingattention to the fact that the shaft multiple angle is 4:

-   (1) pick up a magnetic flux of the spatial first order or the    spatial seventh order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    FIG. 44 shows an example of three-phase windings satisfying the    condition (1). FIG. 45 shows the three-phase windings which are    subjected to the three-phase-to-two-phase conversion in accordance    with expression (4) to satisfy the condition (2). Note that γ=0 and    k=(⅔)^(1/2). However, a number is rounded off to the fourth decimal    place. The realistic numbers of turns which are decided specifically    on the basis of FIG. 45 are shown in FIG. 46. Values obtained by    multiplying the numbers of turns in FIG. 45 by 50 for excitation    windings and 150 for output windings are indicated, respectively.    Note that decimals are rounded off in FIG. 46. A graph of FIG. 47    shows how a voltage appearing in the output windings of two phases    is changed by a rotor position when the winding specifications are    set as shown in FIG. 46 and excitation windings are excited by an AC    current. In this figure, reference numeral 20 denotes an α phase    winding and 21 denotes a β phase winding. In addition, the    horizontal axis indicates a position of a rotor with a machine    angle, and the vertical axis indicates a voltage generated in the    output windings. Note that a minus sign of a voltage indicates that    a phase is reversed with respect to an electric current of the    excitation windings. In both the cases, since voltages deviate by an    electric angle of 90 degrees (machine angle of 22.5 degrees) from    each other in a waveform of a sine wave shape, it could be confirmed    that the output windings operated as the rotation angle detection    device with the shaft multiple angle of 4.

FIG. 48 shows an example in which a shaft multiple angle is 8 and thenumber of teeth is 12. In FIG. 48, reference numeral 1 denotes a stator;2, a rotor; 3, twelve teeth provided in the stator 1; 4, a core of thestator 1; 5, a winding wound around the teeth 3; 6, a core of the rotor2; 7, eight salient poles provided in the core 6; and 10, a rotationangle detection device.

When it is assumed that the number of poles of the excitation winding issix, conditions for the excitation winding 5 to operate as the rotationangle detection device are found as follows in the same manner, payingattention to the fact that the shaft multiple angle is 8:

-   (1) pick up a magnetic flux of the spatial fifth order or the    spatial eleventh order; and-   (2) do not pick up a magnetic flux of the spatial third order or an    integer times thereof.    FIG. 49 shows an example of three-phase windings satisfying the    condition (1). FIG. 50 shows the three-phase windings which are    subjected to the three-phase-to-two-phase conversion in accordance    with expression (4) to satisfy the condition (2). Note that γ=0 and    k=(⅔)^(1/2). However, a number is rounded off to the fourth decimal    place. The realistic numbers of turns which are decided specifically    on the basis of FIG. 50 are shown in FIG. 51. Values obtained by    multiplying the numbers of turns in FIG. 50 by 50 for excitation    windings and 150 for output windings are indicated, respectively.    Note that decimals are rounded off in FIG. 51. A graph of FIG. 52    shows how a voltage appearing in the output windings of two phases    is changed by a rotor position when the winding specifications are    set as shown in FIG. 51 and excitation windings are excited by an AC    current. In this figure, reference numeral 20 denotes an α phase    winding and 21 denotes a β phase winding. In addition, the    horizontal axis indicates a position of a rotor with a machine    angle, and the vertical axis indicates a voltage generated in the    output windings. Note that a minus sign of a voltage indicates that    a phase is reversed with respect to an electric current of the    excitation windings. Since voltages deviate by an electric angle of    90 degrees (machine angle of 11.25 degrees) from each other in a    waveform of a sine wave shape, it could be confirmed that the output    windings operated as the rotation angle detection device with the    shaft multiple angle of 8.

Note that the windings illustrated above are only examples. This isbecause there are other windings which satisfy the condition (1) and, inaddition, the number of turns can also be changed according to γ and k.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of three phases, and then, subjectingthe output windings to the three-phase-to-two-phase conversion.Accordingly, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there isobtained an effect in that a structure is simplified and a manufacturingprocess is facilitated. Moreover, in the conventional examples, thenumber of teeth of a stator is 16 in the case in which a shaft multipleangle is 4, and the number of teeth of the stator is 32 when the shaftmultiple angle is 8, whereas, according to the present invention, thenumber of teeth is twelve. In other words, since the rotation angledetection device of the present invention can be constituted with thesmaller number of teeth than the conventional examples even if the shaftmultiple angle increases, there is also an effect in that the rotationangle detection device has satisfactory winding property and machiningproperty and is excellent in mass productivity. Moreover, in theconventional examples, the number of turns may be changed in a sine waveshape. In this case, there are teeth to which only a small number ofturns are applied. Since positioning of a nozzle of a winding machinefor automatic winding, which requires time, is required to be performedfor the teeth, there is a problem in that efficiency of winding workfalls. In the present invention, as it is evident from FIGS. 46 and 51,there are a plurality of teeth to which output windings may not beapplied, thus having an effect in that efficiency of winding work can beimproved. In addition, since multiphase windings, which are constitutedimaginarily, can be constituted in three phases in constituting outputwindings of two phases, there is an effect in that specifications ofoutput windings can be decided easily.

Sixth Embodiment

The rotation angle detection device of the present invention operates aswindings pick up a magnetic flux generated in a gap between a stator anda rotor. However, the rotation angle detection device may be affected bynoises from the outside. Above all, a magnetic flux generated by amagnetomotive force of the spatial 0^(th) order may adversely affect therotation angle detection device. For example, in a rotation angledetection device with a shaft multiple angle of 4, a magnetic flux ofthe spatial fourth order is generated. This will be described withreference to FIG. 53. In FIG. 53, reference numeral 30 denotes (adirection of) an electric current flowing around a shaft of the rotor 2;31, (a direction of) a magnetomotive force generated by the electriccurrent 30; and 32, a magnetic flux of the same order as a shaftmultiple angle generated by the magnetomotive force 31. For example, asshown in FIG. 53, if the current 30 is flowing around the shaft of therotor 2, the magnetomotive force 31 is generated in a direction parallelwith the shaft of the stator 1. As a result, a magnetomotive force ofthe spatial 0^(th) order is generated between the rotor 2 and the stator1 of the rotation angle detection device 10. On the other hand, therotor 2 has salient poles of the same number as the shaft multipleangle. Thus, since permeance also changes in this order, a magnetic fluxof the same order as the shaft multiple angle is generated in the gap bythe magnetomotive force of the spatial 0^(th) order. In addition, amagnetic flux of the spatial 0^(th) order is also generated. In theconventional rotation angle detection device, there is a problem inthat, when the winding provided in the stator 1 picks up this magneticflux, a detecting position error increases, and an angle cannot bedetected correctly. Thus, in this embodiment, output windings areconstituted so as not to pick up a magnetic flux of a spatial orderwhich is the same as a spatial order of a change in permeance of a rotoror a magnetic flux generated by a magnetomotive force of the spatial0^(th) order to prevent the increase in a detecting position error.

As a specific example, the rotation angle detection device of FIG. 11 inwhich the shaft multiple angle is 4 and the number of teeth is 9 will bedescribed. In this case, since a magnetic flux of the spatial fourthorder is generated by a magnetomotive force of the spatial 0^(th) order,it is sufficient to constitute a winding so as not to pick up themagnetic flux. FIG. 54 shows a vector diagram with respect to thespatial fourth order. First, three-phase windings are constitutedimaginarily. It is sufficient to set a sum of vectors with respect tothe spatial fourth order so as to be zero. In FIG. 15, a U phase windingis applied to the teeth numbers 1, 5, and 6, and polarities are madeopposite in the teeth number 1 and the teeth numbers 5 and 6. Here, byfurther changing the number of turns for the teeth numbers 5 and 6 fromthat for the teeth number 1, it becomes possible not to pick up amagnetic flux of the spatial fourth order. More specifically, it issufficient that there is the following relation between the number ofturns N₅=N₆ of the teeth numbers 5 and 6 and the number of turns N₁ ofthe teeth number 1.

$\begin{matrix}{{N_{1} = {{- 2}\;\cos\frac{4\pi}{9}}}\mspace{20mu}{N_{5} = {{- 2}\cos\frac{4\pi}{9}N_{6}}}} & (5)\end{matrix}$A V phase winding and a W phase winding are set in the same manner toplace the three windings in positions deviating by an electric angle of120 degrees from each other, winding specifications of three phases canbe decided. An example of the windings is shown in FIG. 55. Moreover,FIG. 56 shows windings obtained by further subjecting the windings tothree-phase-to-two-phase conversion. The specific numbers of turns areas shown in FIG. 57. In addition, a total of the number of turns of therespective phases of output windings is zero taking into accountpolarities as well in the winding of FIG. 57. Thus, a magnetic flux ofthe spatial 0^(th) order is not picked up. A graph of FIG. 58 shows howan output voltage changes according to a rotor position in this case. Inthis figure, reference numeral 20 denotes an α phase winding and 21denotes a β phase winding. Since voltages deviate by an electric angleof 90 degrees (machine angle of 22.5 degrees) from each other in awaveform of a sine wave shape, it could be confirmed that the outputwindings operated as the rotation angle detection device with the shaftmultiple angle of 4.

In addition, the rotation angle detection device in which the shaftmultiple angle is 4 and the number of teeth is 9 is described here.However, for example, it is sufficient to adapt the winding using avector diagram so as not to pick up a magnetic flux of the spatial orderwhich is the same as the shaft multiple angle. Thus, the effects can beobtained without depending upon the shaft multiple angle or the numberof teeth.

As described above, the output windings of two phases were obtained byimaginarily defining the windings of three phases and, then, subjectingthe output windings to the three-phase-to-two-phase conversion.Consequently, it was confirmed that the output windings operate as therotation angle detection device. With such a constitution, since thenumber of phases decreases compared with a rotation angle detectiondevice in which excitation is constituted by three phases, there is aneffect in that a structure is simplified and a manufacturing process isfacilitated. Moreover, in the conventional examples, the number of teethof a stator is sixteen in the case in which a shaft multiple angle is 4,whereas, according to the present invention, the number of teeth isnine. In other words, since the rotation angle detection device of thepresent invention can be constituted with the smaller number of teeththan the conventional examples even if the shaft multiple angleincreases, there is also an effect in that the rotation angle detectiondevice has satisfactory winding property and machining property and isexcellent in mass productivity. Moreover, in the conventional examples,the number of turns may be changed in a sine wave shape. In this case,there are teeth to which only a small number of turns are applied. Sincepositioning of a nozzle of a winding machine for automatic winding,which takes time, is required to be performed for the teeth, there is aproblem in that efficiency of winding work falls. In the presentinvention, as it is evident from FIG. 57, there are a plurality of teethto which output windings may not be applied, thus having an effect inthat efficiency of winding work can be improved. In addition, sincemultiphase windings, which are constituted imaginarily, can beconstituted in three phases in constituting output windings of twophases, there is an effect in that specifications of output windings canbe decided easily.

Moreover, in this embodiment, the output windings are constituted suchthat output windings of two phases do not pickup a specific component ofa magnetic flux of the spatial order, which is the same as the spatialorder of a change in permeance of a rotor, or of a magnetic flux whichis generated by a magnetomotive force of the spatial 0^(th) order. Thus,there is also an effect in that an increase in a detecting positionerror is prevented.

Seventh Embodiment

In the above-mentioned embodiments, a shape of a rotor is notspecifically limited. However, a detecting position error may increaseif a shape of a rotor is not appropriate. This embodiment relates to arotation angle detection device which utilizes a component of variationin permeance caused by a shape of a rotor. Here, a detecting positionerror decreases if the component of variation in permeance has a sinewave shape and the rotation angle detection device becomes highlyaccurate.

Therefore, when an angle having a center of a rotation shaft of a rotoras the origin and representing a position on an external circumferenceof the rotor is θ, if permeance between an internal circumference of astator and the external circumference of the rotor is as followsincluding a direct current component in the angle θ, the rotation angledetection device here functions as a highly accurate rotation angledetection device:A+B cos(Mθ)  (6)provided that A and B are positive constants and A>B, and M is a shaftmultiple angle of the rotation angle detection device. If the shape ofthe rotor is set such that a gap length in the position of the angle θis as follows from the fact that the gap length is in inverse proportionto permeance and from expression (6), a pulsation component of permeanceof the gap takes a sine wave shape, and a highly accurate rotation angledetection device can be realized:

$\begin{matrix}\frac{1}{A + {B\;{\cos\left( {M\;\theta} \right)}}} & (7)\end{matrix}$

Therefore, according to this embodiment, the same effects as the firstto the sixth embodiments can be obtained, and there is also an effect inthat a detecting position error can be further reduced and a highlyaccurate rotation angle detection device can be realized by setting thenumbers of turns of output windings as described in any of the first tosixth embodiments and forming the rotor in a shape determined byexpression (7).

Eighth Embodiment

The rotation angle detection device of the present invention operates aswindings pick up a magnetic flux generated in a gap between a stator anda rotor. However, when a rotation shaft of the rotor and a center of thestator deviate from each other, or when a center and the rotation shaftof the rotor deviate from each other, that is, when eccentricity orshaft deviation occurs, it is likely that the rotation angle detectiondevice is affected by a magnetic flux component of a specific order anda detecting position error increases. An order of a magnetic flux causedby eccentricity or shaft deviation is, for example, as described below.

(Order of a Magnetomotive Force of Excitation)±1

The order of a magnetomotive force of excitation is a spatial order of amagnetomotive force generated by an electric current flowing throughexcitation windings. For example, if excitation is by six poles, theorder of a magnetomotive force of excitation is 3. In this case, fromthe above expression.3±1=2, 4

Thus, magnetic fluxes of the spatial second order and the spatial fourthorder are generated. The conventional examples have a problem in thatoutput windings may pick up a magnetic flux of an order generated byeccentricity in this way to cause an increase in a detecting positionerror. Thus, in this embodiment, a constitution of windingspecifications which does not pick up a specific component of such amagnetic flux generated by eccentricity or shaft deviation will bedescribed.

FIG. 59 shows an example of a rotation angle detection device in whichthe number of teeth of a stator is twelve and a shaft multiple angle is8. In FIG. 59, reference numeral 1 denotes a stator; 2, a rotor; 3,twelve teeth provided in the stator 1; 4, a core of the stator 1; 5, awinding wound around the teeth 3; 6, a core of the rotor 2; 7, eightsalient poles provided in the core 6; and 10, a rotation angle detectiondevice. As in the fifth embodiment, excitation windings are applied soas to have six poles. In this case, as already described, in the case inwhich the excitation windings have six poles, magnetic fluxes of thespatial second order and the spatial fourth order are generated in a gapdue to eccentricity and shaft deviation. A constitution of outputwindings which do not pickup these two components will be consideredusing vector diagrams. Vector diagrams with respect to the spatialsecond order and the spatial fourth order are shown in FIGS. 60 and 61,respectively. The vector diagrams indicate in which phase the windingapplied to the respective twelve teeth links with the magnetic fluxes ofthe spatial second order and the spatial fourth order. From the vectordiagrams, it is seen that, for example, vectors of magnetic fluxeslinking with a winding applied to teeth, which are represented by arelation of n, n+2, n+4 (n=1, 2, 3, . . . ) such as the teeth numbers 1,3, and 5, deviate from each other by an electrical angle of 120 degreesand a sum of the vectors is zero. In constituting three-phase windingsimaginarily, if a combination of vectors, in which a sum of the vectorsof the magnetic fluxes of the spatial second order and the spatialfourth order is zero as described above, is selected, even two-phaseoutput windings obtained by three-phase-to-two-phase conversion do notpickup the magnetic fluxes of the spatial second order and the spatialfourth order. In other words, it is considered that even if eccentricityor shaft deviation occurs, an increase in a detecting position error canbe prevented since a specific component of a magnetic flux caused by theeccentricity or shaft deviation is not picked up.

Here, an example of specific winding specifications will be described.FIGS. 62, 63, and 64 show examples of three-phase windings which areconstituted imaginarily. U, V, and W phases deviate by an electricalangle of 120 degrees with respect to each other, and as alreadydescribed, the windings of the respective phases are constituted byapplying a winding to teeth numbers represented by a relation of n, n+2,n+4 (n=1, 2, 3, . . . ) such as the teeth numbers 1, 3, and 5. In FIG.62, the U phase is constituted by the teeth numbers 1, 3, and 5. In FIG.63, the U phase is constituted by the teeth numbers 1, 3, and 5, and 2,4, and 6. In FIG. 64, the U phase is constituted by the teeth numbers 1,3, and 5, and 8, 10, and 12. The V phase and the W phase are constitutedso as to deviate by an electrical angle of ±120 degrees with respect tothe U phase. FIGS. 65, 66, and 67 show these windings converted intotwo-phase output windings according to the three-phase-to-two-phaseconversion. Moreover, FIGS. 68, 69, and 70 show examples of specificnumbers of windings.

In the rotation angle detection device with these three types of windingspecifications (No. 1, No. 2, and No. 3), FIG. 71 shows a detectingposition error for a case in which eccentricity of 0.10 mm is causedbetween a rotor and a stator and for an ideal case in which noeccentricity is caused. For comparison, a result of conventional windingspecifications is also shown. From the results of the windingspecifications, it is quite obvious that, in the conventional windingspecification, a detecting position error extremely increases due toeccentricity, whereas, in the winding specifications of this embodiment,a detecting position error rarely increases even if eccentricity occurs,and the rotation angle detection device functions as a more highlyaccurate rotation angle detection device than in the conventionalexamples.

Hereinabove, the examples of the rotation angle detection device inwhich the number of teeth of a stator is 12 and a shaft multiple angleis 8 is described. However, it is needless to mention that there arewinding specifications with which the same effects can be obtained bythe number of turns other than those described above, and the sameeffects can be obtained as long as output windings are constituted so asnot to pick up a specific order component of a gap magnetic flux whichis generated by eccentricity or shaft deviation, even with other numberof teeth or shaft multiple angle.

As described above, in this embodiment, the same effects as the first tothe seventh embodiments can be obtained. In addition, by adopting theconstitution described in this embodiment as a constitution of outputwindings, an increase in a detecting position error can be prevented,since a specific component of a magnetic flux density is not picked up,which is generated when a rotation shaft of a rotor and a center of astator deviate from each other, that is, when eccentricity or shaftdeviation occurs. In addition, since a detecting position error due toan attaching position error, eccentricity, shaft deviation, or the likedoes not increase, there is also an effect in that cost for improvementof attaching position accuracy can be reduced. In addition, in thewinding specifications described here, even if a shaft multiple angleincreases, a rotation angle detection device can be constituted byreducing the number of teeth of a rotor compared with the conventionalexamples. It is needless to mention that this feature realizes an effectin that the rotation angle detection device has satisfactory windingproperty and machining property and is excellent in mass productivity.Moreover, in the conventional examples, the number of turns may bechanged in a sine wave shape. In this case, there are teeth to whichonly a small number of turns are applied. Since positioning of a nozzleof a winding machine for automatic winding, which requires time, isrequired to be performed for the teeth, there is a problem in thatefficiency of winding work falls. In the present invention, as it isevident from FIGS. 68, 69 and 70 that there are a plurality of teeth towhich output windings may not be applied, and there is an effect in thatefficiency of winding work can be improved which is needless to mention.

Ninth Embodiment

In this embodiment, a case in which the rotation angle detection devicedescribed in the first to the eighth embodiments is used for variousdynamo-electric machines such as a generator and a motor will bedescribed. In the first to the eighth embodiments, it is stated that, byconstituting a winding using multiphase-to-two-phase conversion, arotation angle detection device can be obtained which requires only thesmaller number of teeth of a stator than the conventional examples evenif a shaft multiple angle increases, and is excellent in massproductivity. Since such a rotation angle detecting device isinexpensive and excellent in environmental resistance compared with anoptical encoder, there is an effect in that a system which isinexpensive and excellent in environmental resistance can be establishedif it is used as a rotation angle sensor provided in a dynamo-electricmachine such as a motor or a generator. For example, it is conceivableto incorporate the rotation angle detection device of the presentinvention in a belt driven ISG (Integrated Starter Generator).

FIG. 72 shows a diagram in which the rotation angle detection device ofthe present invention is incorporated in a generator having a field coreof a claw shape. In FIG. 72, reference numeral 1 denotes stator of arotation angle detection device 10; 2, a rotor of the rotation angledetection device 10; 5, an excitation winding wound around teeth 3; 8,an output winding; 40, a generator (or a motor); 41, a field core of thegenerator 40; 42, a shaft; 43, a bearing; 44, a field winding (throughwhich a field current flows); and 45, a stator of the generator 40.

Since a generator (also operating as a motor) is arranged in an engineroom in a system of the belt driven ISG, temperature of the generatorrises. Thus, an optical encoder is not suitable for the generator. Inaddition, the system becomes expensive if the optical encoder is used.Thus, if the rotation angle detection device of the present inventionconstituted by a core and a winding is used, a system which is excellentin environmental resistance, inexpensive, and highly accurate can beestablished. In addition, as described above, since a manufacturingprocess of the rotation angle detection device of the present inventionis easy, a manufacturing process of a dynamo-electric machine using therotation angle detection device is facilitated at least so much more forthat.

Moreover, in the motor or the generator having a field core of a clawshape, a field electric current flows as shown in FIG. 53 to cause amagnetomotive force of the spatial 0^(th) order in a gap of the rotationangle detection device. Therefore, a magnetic flux of a spatial orderwhich is the same as a shaft multiple angle is generated in the gap. Inthe conventional art, the output windings pick up this component, whichleads to an increase in a detecting position error. However, asdescribed in the sixth embodiment of the present invention, if a windingis constituted so as not to pick up a magnetic flux of an order which isthe same as a shaft multiple angle, there is an effect in that theincrease in a detecting position error can be prevented.

Here, only the motor or the generator provided with the field core of aclaw shape is described. However, since a magnetomotive force of thespatial 0^(th) order may be generated in a general motor or generator aswell, it is needless to mention that the increase in a detectingposition error can be prevented by using the rotation angle detectiondevice of the present invention in the motor or the generator.

Further, eccentricity of a rotor may be caused by a machining error suchas an attaching position error. However, since the output windings areconstituted so as not to pick up a specific order component of a gapmagnetic flux generated by eccentricity or shaft deviation as describedin the eighth embodiment, there is an effect in that an increase in adetecting position error due to eccentricity or shaft deviation can beprevented. Moreover, since a detecting position error is not increasedby an attaching position error, eccentricity, shaft deviation, or thelike, there is also an effect in that cost for improvement of attachingposition accuracy can be reduced.

Note that, the first to the ninth embodiments are described with therotation angle detection device which has the stator of output numbersof turns of two phases which can be obtained by converting the number ofturns of multiphase defined imaginarily in advance into two phases, asan example. However, the present invention is not limited to that case,and the number of turns of multiphase may be defined actually ratherthan imaginarily and may be obtained by any other method. In that case,the same effects as described above can also be obtained.

INDUSTRIAL APPLICABILITY

As described above, the rotation angle detection device in accordancewith the present invention is useful as a rotation angle detector whichcan be widely utilized not only for a belt driven ISG (IntegratedStarter Generator) for vehicles but also for various other motors.

1. A rotation angle detection device comprising: a stator provided witha one-phase excitation winding and two-phase output windings; and arotor having salient poles, wherein the two-phase output windings arewound around a plurality of teeth of the stator, and respective numbersof turns of the two-phase output windings are obtained by using m-phasewindings, where m is an integer of 3 or more, the m-phase windings beingdefined in advance to convert the numbers of turns of the m-phasewindings into those of two-phase windings, wherein, when the number ofteeth of the stator is an odd number, a winding pattern of theexcitation winding is a pattern repeated by a number which is the sameas a value of a divisor of the number of teeth.
 2. A rotation angledetection device according to claim 1, wherein the number of teeth ofthe stator is nine, and a shaft multiple angle is 4 or
 8. 3. A rotationangle detection device comprising: a stator provided with a one-phaseexcitation winding and two-phase output windings; and a rotor havingsalient poles, wherein the two-phase output windings are wound around aplurality of teeth of the stator, respective numbers of turns of thetwo-phase output windings are obtained by using m-phase windings, wherem is an integer of 3 or more, the m-phase windinas being defined inadvance to convert the numbers of turns of the m-phase windings intothose of two-phase windings, wherein the number of teeth of the statoris 3n, where n is a natural number, and wherein the number of teeth ofthe stator is nine, and a shaft multipleangle is 4 or
 8. 4. A rotationangle detection device comprising: a stator provided with a one-phaseexcitation winding and two-phase output windings; and a rotor havingsalient poles, wherein the two-phase output windings are wound around aplurality of teeth of the stator, respective numbers of turns of thetwo-phase output windings are obtained by using m-phase windings, wherem is an integer of 3 or more, the m-phase windings being defined inadvance to convert the numbers of turns of the m-phase windinas intothose of two-phase windings, wherein the number of teeth of the statoris 3n. where n is a natural number, and wherein the number of teeth ofthe stator is twelve, and a shaft multiple angle is 4 or
 8. 5. Arotation angle detection device comprising: a stator provided with aone-phase excitation winding and two-phase output windings; and a rotorhaving salient poles, wherein the two-phase output windings are woundaround a plurality of teeth of the stator, respective numbers of turnsof the two-phase output windings are obtained b usin m-phase windings,where m is an integer of 3 or more, the m-phase windings being definedin advance to convert the numbers, of turns of the m-phase windings intothose of two-phase windings, and wherein the numbers of turns of thetwo-phase output windings are adjusted such that the two-phase outputwindings do not pick up a magnetic flux of a spatial order which is thesame as a spatial order of a change in permeance of the rotor or amagnetic flux of a spatial 0^(th) order.
 6. A rotation angle detectiondevice comprising: a stator provided with a one-phase excitation windingand two-phase output windings; and a rotor having salient poles, whereinthe two-phase output windings are wound around a plurality of teeth ofthe stator, respective numbers of turns of the two-phase output windingsare obtained by using m-phase windings, where m is an integer of 3 ormore, the m-phase windings being defined in advance to convert thenumbers of turns of the m-phase windings into those of two-phasewindings, and wherein the numbers of turns of the two-phase outputwindings are adjusted such that the two-phase output windings do notpick up a specific component of a gap magnetic flux which is generatedwhen a rotation shaft of the rotor and a center of the stator deviatefrom each other.
 7. A rotation angle detection device as in any one ofclaims 1, 3, 2, 4, 5 and 6, wherein, when the numbers of turns of them-phase windings, where m is an integer of 3 or more, are convened intotwo-phase windings, the conversion is performed according to thefollowing expression: $\begin{matrix}{N_{\alpha\; i} = {k{\sum\limits_{n = 1}^{m}{N_{ni}{\cos\left( {\gamma + {\frac{2\left( {n - 1} \right)}{m}\pi}} \right)}}}}} \\{N_{\beta\; i} = {k{\sum\limits_{n = 1}^{m}{N_{ni}{\sin\left( {\gamma + {\frac{2\left( {n - 1} \right)}{m}\pi}} \right)}}}}}\end{matrix}$ where γ represents an arbitrary constant, k represents anarbitrary constant excluding zero, a subscript i represents a number ofa tooth, α and β represent two-phase windings after conversion, and nrepresents nth phase before conversion, N_(αi) and N_(βi) represent thenumber of turns of the α-phase and β-phase windings in an ith tooth,respectively, and N_(ni) represents the number of turns of nih phasewinding of the ith tooth.
 8. A dynamo-electric machine comprising: arotation angle detection device having a stator provided with aone-phase excitation winding and two-phase output windings and a rotorhaving salient poles, wherein the two-phase output windings are woundaround a plurality of teeth of the stator, respective numbers of turnsof the two-phase output windings are obtained by using m-phase windings,where m is an integer of 3 or more, the m-phase windings being definedin advance to convert the numbers of turns of the m-phase windings intothose of two-phase windings, and wherein, when the number of teeth ofthe stator is an odd number, a winding pattern of the excitation windingis a pattern repeated by a number which is the same as a value of adivisor of the number of teeth.
 9. The dynamo-electric machine accordingto claim 8, wherein the number of teeth of the stator is nine, and ashaft multiple angle is 4 or
 8. 10. A dynamo-electric machinecomprising: a rotation angle detection device having a stator providedwith a one-phase excitation winding and two-phase output windings and arotor having salient poles, wherein the two-phase output windings arewound around a plurality of teeth of the stator, respective numbers ofturns of the two-phase output windings are obtained by using m-phasewindings, where m is an integer of 3 or more, the m-phase windings beingdefined in advance to convert the numbers of turns of the m-phasewindings into those of two-phase windings, wherein the number of teethof the stator is 3n, where n is a natural number, and wherein thenurnher of teeth of the stator is nine, and a shaft multiple angle is 4or
 8. 11. A dynamo-electric machine comprising: a rotation angledetection device having a stator provided with a one-phase excitationwinding and two-phase output windings and a rotor having salient poles,wherein the two-phase output windings are wound around a plurality ofteeth of the stator, respective numbers of turns of the two-phase outputwindings are obtained by using m-phase windings, where m is an integerof 3 or more, the m-phase windings being defined in advance to convertthe numbers of turns of the m-phase windings into those of two-phasewindings, wherein the number of teeth of the stator is 3n, where n is anatural number, and wherein the number of teeth of the stator is twelve,and a shaft multiple angle is 4 or
 8. 12. A dynamo-electric machinecomprising: a rotation angle detection device having a stator providedwith a one-phase excitation winding and two-phase output windings and arotor having salient poles, wherein the two-phase output windings arewound around a plurality of teeth of the stator, respective numbers ofturns of the two-phase output windings are obtained by using m-phasewindings, where m is an integer of 3 or more, the m-phase windings beingdefined in advance to convert the numbers of turns of the m-phasewindings into those of two-phase windings, and wherein the numbers ofturns of the two-phase output windings are adjusted such that thetwo-phase output windings do not pick up a magnetic flux of a spatialorder which is the same as a spatial order of a change in permeance ofthe rotor or a magnetic flux of a spatial 0^(th) order.
 13. Adynamo-electric machine comprising: a rotation angle detection devicehaving a stator provided with a one-phase excitation winding andtwo-phase output windings and a rotor having salient poles, wherein thetwo-phase output windings are wound around a plurality of teeth of thestator, respective numbers of turns of the two-phase output windings areobtained by using m-phase windings, where m is an integer of 3 or more,the m-phase windings being defined in advance to convert the numbers ofturns of the m-phase windings into those of two-phase windings, andwherein the numbers of turns of the two-phase output windings weadjusted such that the two-phase output wlndings do not pick up aspecific component of a gap magnetic flux which is generated when arotation shaft of the rotor and a center of the stator deviate from eachother.
 14. A dynamo-electric machine as in any one of claims 8, 10-13,9, wherein, when the numbers of turns of the m-phase windings, where mis an integer of 3 or more, are converted into two-phase windings, theconversion is performed according to the following expression:$\begin{matrix}{N_{\alpha\; i} = {k{\sum\limits_{n = 1}^{m}{N_{ni}{\cos\left( {\gamma + {\frac{2\left( {n - 1} \right)}{m}\pi}} \right)}}}}} \\{N_{\beta\; i} = {k{\sum\limits_{n = 1}^{m}{N_{ni}{\sin\left( {\gamma + {\frac{2\left( {n - 1} \right)}{m}\pi}} \right)}}}}}\end{matrix}$ where γ represents an arbitrary constant, k represents anarbitrary constant excluding zero, a subscript i represents a number ofa tooth, α and β represent two-phase windings after conversion, and nrepresents nth phase before conversion, N_(αi) and N_(βi) represent thenumber of turns of the α-phase and β-phase windings in an it tooth,respectively, and N_(ni) represents the number of turns of nth phasewinding of the ith tooth.